170. Action for divorce. 

An action for divorce may be maintained by a husband or wife to procure a judgment  divorcing  the  parties  and dissolving the marriage on any of the following grounds:
(1) The cruel and inhuman treatment of the plaintiff by the defendant such that the conduct of the defendant so endangers the physical or mental well being of the plaintiff as renders it unsafe or improper for the plaintiff to cohabit with the defendant.
(2) The abandonment of the plaintiff by the defendant for a period of one or more years.
(3) The confinement of the defendant in prison for a period of three or more consecutive years after the marriage of plaintiff and defendant.
(4) The commission of an act of adultery, provided that  adultery for the purposes of articles ten, eleven, and eleven-A of this chapter, is hereby defined as the commission of an act of sexual  intercourse, oral sexual conduct or anal sexual conduct, voluntarily performed by the defendant, with a person other than the plaintiff after the marriage of plaintiff and defendant.  Oral sexual conduct and anal sexual conduct include, but are not limited to, sexual conduct  as defined in subdivision two of section 130.00 and subdivision three of section 130.20 of the penal law.
(5) The husband and wife have lived apart pursuant to a decree or judgment of separation  for a period of one or more years after the granting of such decree or judgment, and  satisfactory proof has been submitted by the plaintiff that he or she has substantially performed all the terms and conditions of such decree or judgment.
(6) The husband and wife have lived separate and apart pursuant to a written agreement of separation, subscribed by the parties thereto and acknowledged or proved in the form required to entitle a deed to be recorded, for a period of one or more years after the execution of such agreement and satisfactory proof has been submitted by the plaintiff that he or she has substantially performed all the terms and conditions of such agreement. Such agreement shall be filed in the office of  the clerk of the county wherein either party resides. In lieu of filing such agreement, either party to such agreement may file a memorandum of such agreement, which memorandum shall be similarly subscribed and acknowledged or proved as was the agreement of separation and shall contain the following information: (a) the names and addresses of each of the parties, (b) the date of marriage of the parties, (c) the date of the agreement of separation and (d) the date of this subscription and acknowledgment or proof of such agreement of separation.